At her father's bidding, Yui Komori relocates to a secluded mansion housing the enigmatic Sakamaki brothers—Shuu, Reiji, Ayato, Kanato, Laito, and Subaru—who happen to be vampires. Initially puzzled by Yui's presence, the brothers soon realize she is intended as their new 'sacrificial bride,' entwined with darker desires. Questioning her father's motives and grappling with newfound sensations, Yui's tranquility shatters amidst the sadistic nature of each sibling. Trapped in a world where nights never end, Yui faces escalating torment and passion as the brothers vie for her affections, driving her to the brink of obsession and rapture.